1. Field of the Invention
The present invention relates to a resin material supply apparatus to a resin press molding machine.
2. Description of the Prior Art
Examples of apparatus for supplying a resin material to a mold of a resin press molding machine are shown in FIGS. 7 and 8.
In the FIG. 7 apparatus, a sheet-like resin material 137 is cut, and the thus cut resin materials are manually stacked on a carriage 138 while being adjusted to a shape (a molding pattern) of molds 140 and 141 of a resin press molding machine 139, the thus stacked resin materials 137 being supplied by means of a charging device 142 onto the mold 141 in a manner such that the shape thereof is not altered.
Alternatively, in the FIG. 8 apparatus, a resin material is extruded into a predetermined shape by means of a screw 145 provided within a supply cylinder 144 through a die 146 and then supplied onto the mold 141.
The FIG. 7 apparatus has a problem in that since the manually accomplished step is involved, the resin material supply work to the molds 140 and 141 cannot be performed in an automatic fashion.
There is a further problem in that air enters between the stacked resin materials 137 and cannot be removed, and therefore a surface of a molded product molded by the resin press molding machine 139 is inferior.
The FIG. 8 apparatus is free from the problems as noted above but has the following problem in the case the resin material contains glass fibers.
That is, in the apparatus shown in FIG. 8, the resin material is extruded by the screw 145 to cause it to pass through the die 146. Therefore, it is necessary to make the screw 145 to be of a shallow groove type so that high pressure is applied to the resin material by the screw 145.
Therefore, if the resin material contains the glass fibers, when the resin material passes through the supply cylinder 144, the glass fibers are sometimes broken to deteriorate the strength of the molded product.
Particularly, in the case where the FIG. 8 apparatus makes use of an injection unit, the resin material also passes through a back-flow check valve, and therefore the above-described problem becomes marked.